Temporally and spectrally resolved imaging of laser-induced plasmas

We report a hybrid imaging technique capable of performing measurements of the spatial, temporal, and spectral emission characteristics of laser-induced plasmas by use of a single detection system. We apply this technique to study the plasma produced by laser ablation of LiNbO3 and observe phenomena not seen in such detail with standard instruments. These include extreme line broadening up to a few nanometers accompanied by self-absorption near the target surface, and expansion dynamics that differ strongly between the different species. Overall, the wealth of quantitative information provided by this novel technique sheds new light on processes occurring during plasma expansion.

Real time TaqMan PCR detection and quantitation of HBV genotypes A-G with the use of an internal quantitation standard

BACKGROUND

Diagnostic assays for the accurate quantitation of hepatitis B virus (HBV) DNA levels from patients undergoing antiviral therapy are useful for monitoring and tailoring therapy. Such assays should give accurate results with all HBV genotypes, including a seventh genotype of hepatitis B virus, genotype G, that has recently been identified in specimens from HBV-positive patients in the United States and Europe.

OBJECTIVES

To characterize the performance characteristics of a quantitative real time TaqMan PCR assay, the High Pure System Viral Nucleic Acid/COBAS TaqMan HBV Test, for the detection and quantitation of HBV genotypes A-G from patient plasma and serum. This test was evaluated for limit of detection, dynamic range, reproducibility, accuracy, and genotype inclusivity.

STUDY DESIGN

Primers and TaqMan probes specific for HBV and an internal quantitation standard (QS) were designed and tested using a set of plasmid DNAs representing various genotyped specimens. In addition, sensitivity, dynamic range, precision, and correlation with the COBAS AMPLICOR HBV MONITOR Test were evaluated using HBV dilution panels and patient specimens.

RESULTS AND CONCLUSIONS

A real time TaqMan assay was developed that detects and quantifies DNA from genotypes A-G equivalently. The assay has a limit of detection of <50 copies/ml with plasma and serum, a dynamic range up to 10(9) copies/ml, and good precision and accuracy. Titers obtained with this method without dilutions show good correlation across the dynamic range with titers obtained with the COBAS AMPLICOR HBV MONITOR Test.

Treatment trials in ankylosing spondylitis: current and future considerations

Emerging treatment options in ankylosing spondylitis (AS) are giving new hope to patients with this chronic and potentially disabling disease. Clinical development of new treatments requires that rigorous and well controlled trials be conducted to demonstrate safety and efficacy. A number of classification systems have been developed in recent years as a result of enhanced understanding of the pathogenesis of AS. Although new outcome measures have been developed and a consensus has been reached on the use of assessment instruments in clinical trials, there is still need for improvement and implementation. The ASsessments in Ankylosing Spondylitis (ASAS) Working Group has addressed some of these dilemmas by establishing a core set of domains for the evaluation of AS and by selecting specific assessment methods for each domain. They have also published improvement criteria for assessing short term improvement with symptom modifying antirheumatic drugs and are presently in the process of developing response criteria for disease controlling antirheumatic treatment. Various experts are also currently examining discrepancies and inadequacies of classification systems for AS. Imaging studies, magnetic resonance imaging, in particular, may provide better classification criteria in the near future. In addition to consensus on outcome assessment and classification of AS, lessons learnt from clinical trials in rheumatoid arthritis (RA) may serve as a template for AS. Guidance provided by the United States Food and Drug Administration (FDA) for clinical trials in RA may be of particular use. The FDA has defined the claims that sponsors can receive for RA products and the clinical trial data that would be expected to be submitted to support such claims.

Fluorescence lifetime system for microscopy and multiwell plate imaging with a blue picosecond diode laser

We report a wide-field fluorescence lifetime imaging (FLIM) system that uses a blue picosecond pulsed diode laser as the excitation source. This represents a significant miniaturization and simplification compared with other time-domain FLIM instruments that should accelerate the development of clinical and real-world applications of FLIM. We have demonstrated this instrument in two configurations: a macroimaging setup applied to multiwell plate assays of chemically and biologically interesting fluorophores and a microscope system that has been applied to imaging of tissue sections. The importance of the adjustable repetition rate of this laser source is discussed with respect to noise reduction and precision in the lifetime determination, illustrating a further significant advantage over conventional mode-locked solid-state lasers.

Perceptions of quality and value in state and local pharmacy professional organizations

Officer and member perceptions of the quality and value of the services provided by American Society of Health-System Pharmacists (ASHP) state affiliates and local chapters were studied. A survey was mailed in December 2000 to all 249 state society and local-chapter officers in Ohio, Pennsylvania, New York, Minnesota, and Illinois and a random sample of 1191 members. The survey solicited ratings of the quality and value of programs and services related to continuing education, communications, community service, and membership benefits. Of 1440 surveys mailed, 26 were returned as undeliverable; 308 were returned in usable form, for a total response rate of 22%. The most frequent job categories were hospital staff pharmacist (n = 74), hospital pharmacy manager (n = 66), and hospital clinical pharmacist (n = 49). Overall, members perceived lower quality than officers in clinical and administrative continuing-education programs offered by their local chapters. Members also perceived less value in administrative continuing-education programs than did officers. Member and officer perceptions were similar in the areas of communication and community services. Neither members nor officers appeared to value social functions highly as a membership benefit. A survey of state and local affiliates of ASHP in five states identified several areas where officers and members had different perceptions of the quality and value of services provided by these organizations.

Evaluation of desorption/ionization mass spectrometric methods in the forensic applications of the analysis of inks on paper

Fast atom bombardment and laser desorption mass spectrometry (LDMS) provide molecular level information concerning an ink's composition. Two ink-jet printer inks, Ink A containing the cationic dye Methyl Violet 2B, and Ink B containing the anionic dye, Solvent Black, were studied. Both positive and negative ion detection modes of the mass spectrometer were used. LD may be used for the analysis of inks on paper. Once on paper, the ink's solvent system has evaporated, leaving mainly the dyes behind, which are detected using LDMS. An ink fades with time, indicating that the dyes are degrading. Preliminary results from an accelerated aging study of ballpoint pen ink using UV irradiation confirm that dye degradation products are formed. The degradation chemistry follows an oxidative demethylation process for which all products formed are detected using LDMS. Results suggest that LDMS may be developed to determine the relative age of inks.

Autologous stem cell transplantation for pediatric rheumatic diseases

The National Institute of Allergy and Infectious Disease, National Institutes of Health, convened a workshop entitled The Next Step: Protocol Development for Autologous Stem Cell Transplantation for Pediatric Rheumatic Disease, June 2000, co-chaired by Drs. Karyl Barron and Carol Wallace. The goal of the workshop was to focus on the scientific rationale for stem cell transplantation therapy in the pediatric diseases, unique aspects of this therapy in the pediatric rheumatic diseases, transplantation issues and options, regulatory issues, and development of a DNA repository for these diseases.

Time-domain whole-field fluorescence lifetime imaging with optical sectioning

A whole-field time-domain fluorescence lifetime imaging (FLIM) microscope with the capability to perform optical sectioning is described. The excitation source is a mode-locked Ti:Sapphire laser that is regeneratively amplified and frequency doubled to 415 nm. Time-gated fluorescence intensity images at increasing delays after excitation are acquired using a gated microchannel plate image intensifier combined with an intensified CCD camera. By fitting a single or multiple exponential decay to each pixel in the field of view of the time-gated images, 2-D FLIM maps are obtained for each component of the fluorescence lifetime. This FLIM instrument was demonstrated to exhibit a temporal discrimination of better than 10 ps. It has been applied to chemically specific imaging, quantitative imaging of concentration ratios of mixed fluorophores and quantitative imaging of perturbations to fluorophore environment. Initially, standard fluorescent dyes were studied and then this FLIM microscope was applied to the imaging of biological tissue, successfully contrasting different tissues and different states of tissue using autofluorescence. To demonstrate the potential for real-world applications, the FLIM microscope has been configured using potentially compact, portable and low cost all-solid-state diode-pumped laser technology. Whole-field FLIM with optical sectioning (3D FLIM) has been realized using a structured illumination technique.

Whole-field five-dimensional fluorescence microscopy combining lifetime and spectral resolution with optical sectioning

We report a novel whole-field three-dimensional fluorescence lifetime imaging microscope that incoporates multispectral imaging to provide five-dimensional (5-D) fluorescence microscopy. This instrument, which can acquire a 5-D data set in less than a minute, is based on potentially compact and inexpensive diode-pumped solid-state laser technology. We demonstrate that spectral discrimination as well as optical sectioning minimize artifacts in lifetime determination and illustrate how spectral discrimination improves the lifetime contrast of biological tissue.

Application of the stretched exponential function to fluorescence lifetime imaging

Conventional analyses of fluorescence lifetime measurements resolve the fluorescence decay profile in terms of discrete exponential components with distinct lifetimes. In complex, heterogeneous biological samples such as tissue, multi-exponential decay functions can appear to provide a better fit to fluorescence decay data than the assumption of a mono-exponential decay, but the assumption of multiple discrete components is essentially arbitrary and is often erroneous. Moreover, interactions, both between fluorophores and with their environment, can result in complex fluorescence decay profiles that represent a continuous distribution of lifetimes. Such continuous distributions have been reported for tryptophan, which is one of the main fluorophores in tissue. This situation is better represented by the stretched-exponential function (StrEF). In this work, we have applied, for the first time to our knowledge, the StrEF to time-domain whole-field fluorescence lifetime imaging (FLIM), yielding both excellent tissue contrast and goodness of fit using data from rat tissue. We note that for many biological samples for which there is no a priori knowledge of multiple discrete exponential fluorescence decay profiles, the StrEF is likely to provide a truer representation of the underlying fluorescence dynamics. Furthermore, fitting to a StrEF significantly decreases the required processing time, compared with a multi-exponential component fit and typically provides improved contrast and signal/noise in the resulting FLIM images. In addition, the stretched-exponential decay model can provide a direct measure of the heterogeneity of the sample, and the resulting heterogeneity map can reveal subtle tissue differences that other models fail to show.

Long-term follow-up of twenty patients with adenocarcinoma of the pancreas: resection following combined modality therapy

Long-term follow-up of 5 or more years in 20 patients with initially unresectable cancer of the pancreas that responded to chemoradiation therapy is detailed in this article. All patients underwent resection. Seven or 18 surgical survivors are alive 50 or more months.

Ultrafast laser-induced phase transitions in amorphous GeSb films

Time-resolved measurements of the spectral dielectric function reveal new information about ultrafast phase transitions induced by femtosecond laser pulses in Sb-rich amorphous GeSb films. The excitation generates a nonthermal phase within 200 fs. The dielectric function of this phase differs from that of the crystalline phase, contrary to previous suggestions of a disorder-to-order transition. The observed dielectric function is close to that of the liquid phase, indicating an ultrafast transition from the amorphous phase to a different disordered state.

Genetic-susceptibility factor and malignant mesothelioma in the Cappadocian region of Turkey

Erionite present in stones used to build the villages of Karain and Tuzköy, Turkey, mined from nearby caves, is purported to cause mesothelioma in half of the villagers. We constructed genetic epidemiology maps to test whether some villagers were genetically predisposed to mesothelioma. Analysis of a six-generation extended pedigree of 526 individuals showed that mesothelioma was genetically transmitted, probably in an autosomal dominant way. This finding should lead to preventive strategies to lower the incidence of mesothelioma in future generations, and close monitoring of high-risk individuals might allow early detection and cure.

Whole-field optically sectioned fluorescence lifetime imaging

We describe a novel three-dimensional fluorescence lifetime imaging microscope that exploits structured illumination to achieve whole-field sectioned fluorescence lifetime images with a spatial resolution of a few micrometers.

Childhood physical and sexual abuse as risk factors for heavy drinking among African-American women: a prospective study

OBJECTIVE

This study examines the associations among characteristics of child sexual abuse. childhood physical abuse, lack of parental care, and heavy drinking in a relatively young, urban population of African-American women all of whom have documented histories of child sexual abuse.

METHODOLOGY

The sample consists of 113 African American child victims who were brought to a city hospital emergency room for treatment and collection of forensic evidence in the 1970s and re-interviewed as adults in the 1990s.

RESULTS

The results of this research suggest that multiple incidents of child sexual abuse, more than the characteristics of such abuse is an important predictor of adult heavy alcohol use and binge drinking. These results remain even after controlling for the effects of parental drinking behavior.

CONCLUSION

Although the victim of multiple child sexual assaults is more likely to suffer force and penetration, these analyses suggest that it is the multiple victimization and not the force or penetration that drives the relationship between child sexual assault and drinking behaviors.

Maximum suppression of HIV replication leads to the restoration of HIV-specific responses in early HIV disease

OBJECTIVES

It is predicted that HIV-infected individuals in early HIV disease are the most likely group to achieve immune reconstitution following highly active antiretroviral treatment. We assessed whether suppression of HIV replication in this group would improve immune function.

METHODS

Seventeen antiretroviral-naïve patients in early HIV disease were evaluated for immune function and lymphocyte phenotyping using standard immunological assays.

RESULTS

Absolute CD4+ T-cell number increased from a median of 550 to 800 x 10(6) cells/l while CD8+ T-cell numbers were reduced. The decrease in CD8+ cells correlated with a decrease in the CD8+ memory phenotype. Kinetics of CD4+ naïve and memory T-cell rise indicated that 80% of the maximum CD4+ naïve increase was achieved within 18 weeks whereas maximum CD4+ memory T-cell rise was achieved within 36 weeks. Activation markers (HLA-DR, CD38) and an apoptosis-related marker (CD95) were reduced on CD4+ and CD8+ T cells. Lymphocyte proliferation responses to tetanus toxoid, alloantigen, and anti-CD3/CD28 were restored in patients that were initially unresponsive. At baseline, 31% of the patients responded to HIV p24, which increased to 69% post-therapy. The inducible RANTES response was normalized following therapy whereas inducible interferon-gamma, interleukin (IL)-12, and MIP1beta were elevated. The depressed inducible IL-10 response, however, was not altered after therapy.

CONCLUSIONS

This is one of the first studies to demonstrate the restoration of HIV-1 specific responses in non-acute HIV infection, suggesting early intervention with potent antiretroviral therapy may reverse immune-mediated damage not seen with treated patients who have more advanced disease.